Salicylaldimines



United States Patent Ofice US. Cl. 260-566 2 Claims ABSTRACT OF THEDISCLOSURE Salicylaldimines having the formula:

in which R is an alkyl group having from about 8 to about 18 carbonatoms, are employed as antioxidants and anticorrosion agents in organiccompositions. A method for the preparation of these compounds is alsodescribed.

CROSS-REFERENCE TO RELATED APPLICATIONS Application Ser. No. 508,563,filed Nov. 18, 1965 (parent application).

BACKGROUND OF THE INVENTION Field of the invention This invention, whichis a division of our application Ser. No. 508,563, filed Nov. 18, 1965,relates to improved organic compositions and, in one of its aspects,relates more particularly to improved organic compositions in the formof liquid and soild hydrocarbons that are normally susceptible todeterioration by corrosion or oxidation. Still more particularly, inthis aspect, the invention relates to improved organic compositions inthe form of petroleum distillate hydrocarbon fuels, lubricating oils andgreases which, in their uninhibited state, tend to react with andcorrode metal surfaces with which they may come into contact inperforming their intended functions.

Description of the prior art It is well known that certain types oforganic compounds are normally susceptible to deterioration by oxidationor by corrosion when coming into contact with various metal surfaces.For example, it is known that liquid hydrocarbons in the form of fueloils or lubricating oils tend to accumulate considerable quantities ofwater when maintained for long periods of time in storage vessels; andwhen subsequently brought into contact with metal surfaces in theirfunctional environments, deterioration of equipment as a result ofcorrosion, occurs. In addition, where such lubricating oils or-othercorrosioninducing materials are incorporated into solid lubricants as inthe form of greases, similar deleterious results are encountered, thusclearly indicating the necessity for incorporating into such organiccompositions an effective antioxidant and rust-inhibiting agent.

Patented June 10, 1969 SUMMARY OF THE INVENTION It has now been foundthat the aforementioned oxidative and corrosive properties of organiccompositions, particularly in the form of fuels and lubricants, can beeffectively overcome by incorporating therein, as an antioxidant andanti-corrosion agent, small amounts of a salicylaldimine of the groupconsistnig of:

and

in which R is an alkyl group having from about 8 to about 18 carbonatoms.

In general, the present invention, in its preferred applications,contemplates organic compositions which are normally susceptible tooxidative and corrosive deterioration, containing a small amount of theaforementioned salicylaldimine usually from about .001 to about 10percent, by weight, of the total of such compositions. When thissalicylaldimine is incorporated into liquid hydrocarbon compositions,such as jet fuels, turbine fuels, gasolines and the like, or inlubricatnig oils, it is preferably employed in an amount from about .001to about .01 percent, by weight, of the total composition. When thesalicylaldimine is incorporated into a hydrocarbon grease composition,it is preferably employed in an amount from about 0.1 to about 5percent, by weight, of the total grease.

The organic compounds improved in accordance with the present inventionmay comprise any materials that are normally susceptible todeterioration by oxidation or corrosion, in the manner previouslydescribed. A field of specific applicability is the improvement ofliquid hydrocarbons in accordance with the present invention, boilingfrom about F. to about 750 F. Of particular significance is thetreatment of petroleum distillate fuel oils having an initial boilingpoint from about 75 F. to about F. and an end boiling point from about250 F. to about 750 F. It should be noted, in this respect, that theterm distillate fuel oils is not intended to be restricted tostraight-run distillate fractions. These distillate fuel oils can bestraight-run distillate fuel oils, catalytically or thermally cracked(including hydrocracked) distillate fuel oils, or mixtures ofstraight-run distillate fuel oils, naphthas and the like, with crackeddistillate stocks. Moreover, such fuel oils can be treated in accordancewith well-known commercial methods, such as acid or caustic treatment,hydrogenation, solvent-refining, clay treatment, and the like.

The distillate fuel oils are characterized by their relatively lowviscosity, pour point and the like. The principal property whichcharacterizes these contemplated hydrocarbons, however, is theirdistillation range. As hereinbefore indicated, this range will liebetween about 75 F. and about 750 F. Obviously, the distillation rangeof each individual fuel oil will cover a narrower boiling range,falling, nevertheless, within the above-specified limits. Likewise, eachfuel oil will boil substantially, continuously, throughout itsdistillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2 and 3 fueloils, used in heating and as diesel fuel oils, gasoline and the jetcombustion fuels, as previously indicated. The domestic fuel oilsgenerally conform to the specifications set forth in ASTM SpecificationD396-48T. Specification for diesel fuels are defined in ASTMSpecification D975-48T. Typical jet fuels are defined in MilitarySpecification MILF5624B. In addition, as previously indicated,hydrocarbon lubricating oils of varying viscosity and pour points,falling both within and outside the indicated ranges for theaforementioned fuel oils, may also be effectively treated through theuse of the aforementioned salicylaldimines, as antioxidation andanti-corrosion agents.

As previously indicated, the aforementioned salicylaldimines may also beincorporated, as an anti-corrosion agent, in grease compositions. Suchgreases may comprise a combination of a wide variety of lubricatingvehicles and thickening or gelling agents. Thus, greases in which theaforementioned salicylaldimines are particularly effective, may compriseany of the conventional hydrocarbon oils of lubricating viscosity, asthe oil vehicle, and may include mineral or synthetic lubricating oils,aliphatic phosphates, esters and di-esters, silicates, siloxanes andoxyalkyl ethers and esters. Mineral lubricating oils, employed as thelubricating vehicle, may be of any suitable lubricating viscosity rangefrom about SSU at 100 F. to about 6,000 SSU at 100 F., and, preferably,from about 50 to about 250 SSU at 210 F. These oils may have viscosityindexes varying from below 0 to about 100 or higher. Viscosity indexesfrom about to about are preferred. The average molecular weights ofthese oils may range from about 250 to about 800. The lubricating oil isemployed in the grease composition in an amount sufificient toconstitute the balance of the total grease composition, after accountingfor the desired quantity of the thickening agent, and other additivecomponents to be included in the grease formulation.

As previously indicated, the oil vehicles employed in the novel greaseformulations of the present invention, in which the aforementionedsalicylaldimines are incorporated as an antioxidative or anti-corrosionagent, may comprise mineral or synthetic oils of lubricating viscosity.When high temperature stability is not a requirement of the finishedgrease, mineral oils having a viscosity of at least 40 SSU at F., andparticularly those falling within the range from about 60 SSU to about6,000 SSU at 100 F. may be employed. In instances, where syntheticvehicles are employed rather than mineral oils, or in combinationtherewith, as the lubricating vehicle, various compounds of this typemay be successfully utilized. Typical synthetic vehicles include:polypropylene, polypropylene glycol, trimethylol propane esters,neopentyl and pentaerythritol esters, di-(Z-ethyl hexyl) sebacate,di-(Z-ethyl hexyl) adipate, di-butyl phthalate, fluorocarbons, silicateesters, silanes, esters of phosphorus-containing acids, liquid ureas,ferrocene derivatives, hydrogenated mineral oils, chain-typepolyphenyls, siloxanes and silicones (poly-siloxanes), alkyl-substituteddiphenyl ethers typified by a butyl-substituted bis (p-phenoxy phenyl)ether, phenoxy phenyl ethers, etc.

The lubricating vehicles of the aforementioned improved greases of thepresent invention containing the above-described salicylaldimines asadditives, are combined with a grease-forming quantity of a thickeningagent. For this purpose, a wide variety of materials may be employed.These thickening or gelling agents may include any of the conventionalmetal salts or soaps, which are dispersed in the lubricating vehicle ingrease-forming quantities, in such degree as to impart to the resultinggrease composition, the desired consistency. Other thickening agentsthat may be employed in the grease formation may comprise the non-soapthickeners, such as surface-modified clays and silicas, aryl ureas,calcium complexes and similar materials. In general, grease thickenersmay be employed which do not melt and dissolve when used at the requiredtemperature within a particular environment; however, in all otherrespects, any material which is normally employed for thickening orgelling hydrocarbon fluids for forming greases, can be used in preparingthe aforementioned improved greases in accordance with the presentinvention.

The salicylaldimines of the present invention may be prepared, ingeneral, by condensing a salicylaldehyde and a diamine having thestructural formula in which R is an alkyl group having from about 8 toabout 18 carbon atoms. The diamines employed for this purpose arecommercially available under the trade name Duomeens, and aremanufactured by Armour Industrial Chemical Company. Duomeen C has anaverage molecular weight of about 320, and Duomeen T and Duomeen S, eachhave an average molecular weight of about 400. As the aforementionedstructural formula indicates, the Duomeens contain both a primary and asecondary amine group.

More specifically, the novel salicylaldimines of the pres ent inventionare prepared by condensing either one mole of salicylaldehyde with onemole of the diamine, or by condensing three moles of salicylaldehydewith two moles of the diamine. The condensation reaction of one mole ofsalicylaldehyde with one mole of the diamine is represented as follows:

CHO

+HzNCHzCHzCI-IzNHR The condensation reaction of three moles ofsalicylaldehyde with two moles of the diamine is represented as follows:

In each of the above condensation reactions, R represents an alkyl grouphaving from about 8 to about 18 carbon atoms.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following examples will serve toillustrate the preparation of the aforementioned novel salicylaldiminesof the present invention and to demonstrate the elfectiveness thereof inorganic compositions which are normally susceptible to deterioration byoxidation and corrosion,

EXAMPLE 1 A mixture of 300 grams (0.75 mole) of Duomeen T, 91.5 grams(0.75 mole) of salicylaldehyde and 150 cc. of xylene was refluxed at 150C. for 2 hours. This mixture was then gradually heated to 200 C. and wasmaintained at that temperature until water stopped coming over. Thefinal product was clear and fluid at room temperature.

EXAMPLE 2 A'mixture of 300 grams (0.75 mole) of Duomeen S, 91.5 grams(0.75 mole) of salicylaldehyde and 150 cc. of xylene was refluxed at 150C. for hours. This mixture was then gradually heated to 250 C. and wasmaintained at that temperature until water stopped coming over. Thefinal product was clear and fluid at room temperature.

EXAMPLE 3 A mixture of 200 grams (0.5 mole) of Duomeen T, 91.5 grams(0.75 mole) of salicylaldehyde and 100 cc. of benzene was refluxed at125 C. for 3 hours. This mixture was then gradually heated to 150 C. andwas maintained at that temperature until water stopped coming over. Thefinal product was clear and fluid at room temperature.

EXAMPLE 5 A mixture of 200 grams (0.5 mole) of Duomeen S, 91.5 grams(0.75 mole) of salicylaldehyde and 100 cc. of benzene was refluxed at125 C. for 3 hours. This mixture was then gradually heated to 150 C. andwas maintained at that temperature until water stopped coming over. The=final product was clear and fluid at room temperature.

The anti-screen clogging characteristics of fuel oils, havingincorporated therein the novel salicylaldimines of the presentinvention, were determined from a standard screen clogging test. Thistest is conducted using a Sundstrand V3 or S1 home fuel oil burner pumpwith a selfcontained 100-mesh Monel metal screen. About 0.05 percent, byweight, of naturally-formed fuel oil sediment, composed of fuel oil,water, dirt, rust, and organic sludge is mixed with liters of the fueloil. This mixture is circulated by the pump through the screen for 6hours. Then, the sludge deposit on the screen is washed off with normalpentane and filtered through a tared Gooch crucible. After drying, thematerial in the Gooch crucible is washed with a 50-50 (volume)acetonemethanol mixture. The total organic sediment is obtained byevaporating the pentane and the acetone-methanol filtrates. Drying andweighing the Gooch crucible yields the amount of inorganic sediment. Thesum of the organic and inorganic deposits on the screen can be reportedin milligrams recovered or converted into percent screen clogging.

EXAMPLE 6 The salicylaldimines prepared in accordance with the foregoingExamples 1 through 5 were individually blended in test fuel oilscomprising a blend of 60 percent distillate stock obtained fromcontinuous catalytic cracking and 40 percent straight-run distillatestock, having a boiling range of between about 320 F. to about 640 F.,and typical of No. 2 fuel oils. Each blend was subjected to theabove-described screen clogging test. The test results obtained, are setforth in the following Table I:

TABLE I.SCREEN OLOGGING TESTS Goncn., Lb./ Screen Clog- Inhibitors 1,000bbls. ging, Percent Uninhibited fuel blend 0 Uninhibited fuel blend plusEx. 1. 50 5 Uninhibited fuel blend plus Ex. 2 100 4 Uninhibited fuelblend plus Ex. 3 20 50 Uninhibited fuel blend plus Ex. 4 30 47Uninhibited fuel blend plus Ex. 30 42 In order to determine thesedimentation characteristics of fuel oils in which the novelsalicylaldimines of the present invention are incorporated, the 100 F.Fuel Oil Storage Test, was employed. In this test a SOD-millilitersample of the fuel oil under test is placed in a convected ovenmaintained at 100 F. for a period of 12 weeks. Thereafter, the sample isremoved from the oven and cooled. The cooled sample is filtered througha tared asbestos filter (Gooch crucible) to remove insoluble matter. Theweight of such matter in milligrams is reported as the amount ofsediment. A sample of the blank uninhibited oil is run along with a fueloil blend under test. The effectiveness of a fuel oil containing aninhibitor is determined by comparing the weight of sediment formed inthe inhibited oil with that formed in the uninhibited oil.

EXAMPLE 7 The salicylaldimines prepared in accordance with the foregoingExamples 1 through 5, were individually blended in test fuel oilssimilar to the aforementioned test fuel oils employed in theaforementioned screen clogging tests. The test results comparing theblended fuels, containing the novel salicylaldimines of the presentinvention, and uninhibited fuels are set forth in Table II below:

TABLE II.-FUEL OIL STORAGE TESTS [Twelve Weeks Storage at F.]

Conen., Lb./

Sediment,

Inhibitors 1,000 bbls. mgJliter Uninhibited fuel blend 0 36 Uninhibitedfuel blend plus Ex. 1- 100 3 Uninhibited fuel blend 0 107 Uninhibitedfuel blend plus Ex. 100 61 Uninhibited fuel blend 0 131 Uninhibited fuelblend plus Ex. 3 30 34 Uninhibited fuel blend 0 131 Unmhibited fuelblend plus Ex 4. 30 28 Uninhibited fuel blen 0 13 l Uninhibited fuelblend plus Ex. 5- 30 29 A similar storage test was performed withrespect to the salicylaldimines prepared in accordance with theforegoing Examples 3, 4 and 5, which were incorporated in a gasolineblend comprising 100 percent catalytically cracked component, andboiling within the range from approximately 100 F. to approximately 400F., and containing 3 cc. of tetraethyl lead per gallon, as shown inTable III.

It will be seen from Table III, above, that a marked decrease in ASTMgum content is observed with respect to the. aforementioned gasolineblend containing the specified salicyladimines, as compared, in eachinstance, with the same gasoline blend, but not containing thesalicylaldimine additive.

From the foregoing it will be apparent that the salicylaldimineadditives of the present invention are markedly effective in inhibitingclogging and deterioration of hydrocarbon compositions by corrosion andoxidation, and particularly with respect to the treatment of suchhydrocarbons as petroleum distillate fuels.

Furthermore, although the present invention has been described withpreferred embodiments, it will be understood that modifications andvariations may be resorted to, without departing from the spirit andscope of this invention, as those skilled in the art will readilyunderstand.

We claim. 1. A salicylaldimine having the structural formula:

CH=NCHzCHzCH2NR in which R is an alkyl group having from about 8 to 30two moles of a diamine having the structural formula H NCH CH CH NHR toobtain a salicylaldimine having the structural formula:

OH l OII=NOH2CH2CH;NR

GH=NOHzCHzOHzNR in which R is an alkyl group having from about 8 toabout 18 carbon atoms.

20 References Cited UNITED STATES PATENTS 3,031,278 4/ 1962 Buckmann44-73 FOREIGN PATENTS 598,944 5/ 1960 Canada.

LEON ZITVER, Primary Examiner.

MATTHEW M. JACOB, Assistant Examiner.

US. Cl. X.R.

